Musculoskeletal problems are pervasive throughout the population in all age groups and in both sexes. Half of Americans will need services for fractures or bone fusions at some point in their lifetime according to a widely published article presented at the 2003 annual meeting of the American Academy of Orthopedic Surgeons (AAOS). More than $10 billion per year is spent in the United States on hospital care associated with fracture treatment according to this article.
In many cases, arthrodetic procedures are used to treat musculoskeletal problems associated with various joints of patients. Arthrodetic procedures and arthrodesis, as used herein, refer to the surgical immobilization of a joint resulting from fusion of bones of the joint. Arthrodesis of the foot and ankle is a commonly utilized procedure for the treatment of multiple etiologies of foot and ankle pathology, including post-traumatic arthritis, inflammatory arthropathy, seronegative arthropathy, significant joint instability, suboptimal alignment and/or pain. Midfoot, hindfoot, and ankle fusion procedures, such as the triple (three hindfoot articulations), subtalar, talonavicular, and ankle fusions involve the treatment principles of taking down any residual cartilage to the subchondral surface at the level of the involved joint without disturbing its anatomy, stabilizing the joint thereafter with rigid fixation, placing autograft bone (harvested locally or from iliac crest) or other appropriate fusion preparation into surrounding interstices and defects across the joint surface, followed by a relatively standard post-operative regimen of short term immobilization, physical therapy, and gradually increasing load on the fusion site(s).
The time to healing after fusion procedures is longer than that after more conservative treatment methods due to the time required for fusion/union. Historically, an average of two to three months are needed to achieve complete bony union and full weight bearing (FWB) status after these operations. Nonunion rates of other midfoot, hindfoot, and ankle fusion procedures (0-40%) may be higher than those cited for the forefoot. The literature consensus on non-union rates associated with foot and ankle procedures is approximately 10% (See, e.g., Easley et al., Isolated Subtalar Arthrodesis, JBJS, 82-A(5), 2000 pp. 613-624). Nonunions will be detected by 4 and 8 months radiographically and are generally clinically well established by 6-9 months (hence the clinically accepted standard of 4-5 months without evidence of bony progression to declare delayed union and 9 months for declaring nonunion).
Arthrodetic procedures, including arthrodesis of the foot and ankle, often utilize autologous bone grafts to facilitate sufficient bone healing. Autologous bone grafts are widely used due to the fact that there is no risk of cross-contamination associated with allografts or xenografts. Clinical difficulties, nevertheless, exist with autologous bone grafts. Most of these difficulties result from the harvest of the bone graft, including increased operative time, hospital stay and cost, increased blood loss, post-operative pain, risk of infection and/or fracture. Other reported complications associated with autograft include a potential nidus for infection associated with avascular bone, limited tissue supply, and variability in cellular activity of the bone graft (See e.g., Morbidity at bone graft donor sites, J Orthop Trauma 1989, 3, pp. 192-195). In addition to these complications, there is a limited amount of bone graft that may be harvested for use as a bone void filler.
In view of the difficulties associated with autologous bone grafts, it would be desirable to provide alternative osteogenic regeneration systems. It would additionally be desirable to provide methods of using alternative osteogenic regeneration systems in bone fracture treatments and arthrodetic procedures, including foot and ankle arthrodesis.